The Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, La Jolla, California, USA.
J Neuroendocrinol. 1990 Feb 1;2(1):65-9. doi: 10.1111/j.1365-2826.1990.tb00394.x.
Abstract Corticotropin-releasing factor (CRF-41) is the primary mediator of adrenocorticotropin secretion from the adenohypophysis. This 41-amino-acid peptide is synthesized in perikarya of the paraventricular nuclei, transported to nerve terminals in the external zone of the median eminence and released into the hypophysial-portal circulation. It is also synthesized in multiple extrahypothalamic and peripheral sites. In addition, immunoreactive (ir) CRF-41 is present in the systemic circulation, raising the possibility that systemic measurements might provide a useful index of hypothalamic irCRF-41 secretion. This hypothesis was tested in several rat models. Neither bilateral destruction of hypothalamic irCRF-41 producing perikarya, nor infundibular stalk transection altered peripheral plasma irCRF-41 concentration. Furthermore, central administration of norepinephrine, an agent previously shown to evoke irCRF-41 secretion into the portal circulation, was without effect on peripheral irCRF-41 concentration. Finally, while increased irCRF-41 levels in both the hypophysial-portal and the peripheral circulation were associated with nitroprusside-induced hypotension, bilateral paraventricular nuclei lesions blocked irCRF-41 secretion into the hypophysial-portal circulation without blunting the rise observed in the peripheral circulation. The source of peripheral irCRF-41 remains undetermined; however, the adrenals may be excluded as bilateral adrenalectomy failed to alter circulating irCRF-41 levels. Therefore, our observations do not support the concept that peripheral irCRF-41 levels provide a useful index of hypothalamic secretion of this peptide into the hypophysial-portal circulation under the conditions tested.
摘要 促肾上腺皮质激素释放因子 (CRF-41) 是促肾上腺皮质激素从腺垂体分泌的主要介质。这种 41 个氨基酸的肽在室旁核的神经元胞体中合成，被运输到正中隆起的外部区的神经末梢，并释放到垂体门脉循环中。它也在多个下丘脑外和外周部位合成。此外，免疫反应性 (ir) CRF-41 存在于全身循环中，这使得全身测量可能提供下丘脑 irCRF-41 分泌的有用指标。这一假说在几种大鼠模型中得到了检验。下丘脑 irCRF-41 产生神经元的双侧破坏或漏斗柄横断均未改变外周血浆 irCRF-41 浓度。此外，先前显示可诱发 irCRF-41 分泌到门脉循环的去甲肾上腺素的中枢给药对外周 irCRF-41 浓度没有影响。最后，虽然垂体门脉和外周循环中 irCRF-41 水平的升高与硝普钠引起的低血压有关，但双侧室旁核损伤阻断了 irCRF-41 分泌到垂体门脉循环，而没有使外周循环中观察到的升高减弱。外周 irCRF-41 的来源仍不确定；然而，肾上腺可以被排除在外，因为双侧肾上腺切除术未能改变循环中的 irCRF-41 水平。因此，我们的观察结果不支持外周 irCRF-41 水平提供了一个有用的指标，表明在测试条件下，这种肽从下丘脑分泌到垂体门脉循环中的概念。
